The invention concerns a radio controlled timepiece having an outer casing for containing clockworks components, including a time display, an antenna for receiving radio signals to control the time display, and a receiver connected to the antenna and to the time display.
Such a basic mechanism is known from European Publication No. 0 242 712-A2. Within such a timepiece casing, but outside the structure of the electro-mechanical mechanism is located the ferrite rod of a magnetic long wave antenna. The antenna is connected by means of a flexible twin-core cable to the permanently tuned receiver for the demodulation of binary coded signals. Those time signals supply instantaneous absolute time information whereby the display of time, for example the setting of the hands of an electro-mechanical analog display, may be monitored and potentially corrected, as described in more detail for example in Allgaier et al U.S. Pat. No. 4,645,357.
In the case of very small radio timepieces, such as for example radio-controlled wristwatches, it is known from DE-GM 88 15 967, to locate the magnetic long wave antenna not only outside the mechanism, but even outside the watch case housing, i.e., in the watch band articulated onto the case. This obviously restricts the freedom of the designer designing the watch band.
Such restrictions also apply to wristwatches wherein the outer casing is made of ferrite and defines the antenna core as disclosed in European Publication No. 0 382 130-A2. In particular, as the result of such an arrangement, the configuration of the wristwatch casing becomes more complex, and safe electrical connections between the core defined by the casing and a circuit located in the casing are very difficult and expensive.
In view of these conditions, it is an object of the invention to provide a small radio timepiece, in particular in the form of a wristwatch, wherein creative freedom is preserved and connection complications are avoided.